67 research outputs found
O uso da pesquisa-ação para a avaliação e o aprimoramento de práticas integradas para a vigilância da qualidade da água para consumo humano: potencialidades e desafios
Relação entre a presença de vegetação herbácea e a regeneração natural de espécies lenhosas em pastagens abandonadas na Floresta Ombrófila Densa do Sul do Brasil
Reviews : Philadelphia: Neighborhoods, Division and Conflict in a Postindustrial City Carolyn Adams, David Bartelt, David Elesh, Ira Goldstein, Nancy Kleniewski, and William Yancey Temple University Press, Philadelphia, Pennsylvania, 1991. 210 pages. 45.00 (HB), $16.00 (PB
Detailed analysis of the pulsations during and after burst from the bursting pulsar (GRO J1744-28)
Rapid Cooling of the Neutron Star in the Quiescent Super-Eddington Transient XTE J1701--462
Rapid cooling of the neutron star in the quiescent super-Eddington transient XTE J1701-462
Rapid Cooling of the Neutron Star in the Quiescent Super-Eddington Transient XTE J1701--462
We present Rossi X-Ray Timing Explorer and Swift observations made during the final three weeks of the 2006-2007 outburst of the super-Eddington neutron star (NS) transient XTE J1701-462, as well as Chandra and XMM-Newton observations covering the first sime800 days of the subsequent quiescent phase. The source transitioned quickly from active accretion to quiescence, with the luminosity dropping by over 3 orders of magnitude in sime13 days. The spectra obtained during quiescence exhibit both a thermal component, presumed to originate in emission from the NS surface, and a non-thermal component of uncertain origin, which has shown large and irregular variability. We interpret the observed decay of the inferred effective surface temperature of the NS in quiescence as the cooling of the NS crust after having been heated and brought out of thermal equilibrium with the core during the outburst. The interpretation of the data is complicated by an apparent temporary increase in temperature sime220 days into quiescence, possibly due to an additional spurt of accretion. We derive an exponential decay timescale of sime120[superscript +30][subscript –20] days for the inferred temperature (excluding observations affected by the temporary increase). This short timescale indicates a highly conductive NS crust. Further observations are needed to confirm whether the crust is still slowly cooling or has already reached thermal equilibrium with the core at a surface temperature of sime125 eV. The latter would imply a high equilibrium bolometric thermal luminosity of sime5 × 10[superscript 33]ergs[superscript –1] for an assumed distance of 8.8 kpc.Astronomical Society of India (contract I/088/06/0)Chandra X-ray Center (U.S.) (Chandra Award GO7-8049X)Chandra X-ray Center (U.S.) (Chandra Award GO9-0057X
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